1. Field of the Invention
Most patients suffering from peripheral atherosclerotic vascular illnesses or from heart pathologies such as coronary ischemia need substitutive vascular ducts so as to retrieve vascular continuity, or valve substitutes so as to retrieve heart valve function.
2. Prior Art
As far as vascular ducts are concerned, until today no biological synthetic substitute has been able to reproduce the characteristics of vascular ducts in living beings.
Vascular substitutes made of mechanically resistant synthetic materials, such as for instance polytetrafluoroethylene (Teflon®), expanded polytetrafluoroethylene (ePTFE) and polyethyleneterephtalate (Dacron®), are at present the most frequently used thanks to their good behavior as large-diameter vascular ducts.
These materials are used for instance to replace abdominal aorta where diameters are around 10 mm. However, in order to replace smaller diameters the duct opening (artery) can be damaged and unsatisfying.
The most frequent cause for the unsuccessful use of small vascular prostheses consists in thrombotic deformations that may occur on the interface blood-prosthesis inner surface and in the development of intimal hyperplasia on anastomoses, with proliferation and migration of muscular cells and subsequent vessel occlusion.
For these reasons, in common aorta-coronary by-pass surgery concerning vessels whose diameter is of about 3 mm, autologous blood vessels are generally used, such as saphena or inner mammary artery.
However, in a high percentage of patients saphena or other veins cannot be used due to pre-existing pathologies or because they have already been used previously.
Therefore, there is the need for a new material without the drawbacks of prior art. In particular, there is the need for a new material enabling the preparation of vascular ducts and of valve substitutes that have a small diameter and are biocompatible, hemocompatible and biostable towards living tissues.